Field
The present invention relates to a method and apparatus for controlling a downlink HARQ timing in a TDD environment, and more particularly, to a method and apparatus for controlling a downlink HARQ timing of a CA system.
Discussion of the Background
As communication systems have developed, various wireless terminals have been utilized by consumers, including companies and individuals. A current mobile communication system affiliated with 3GPP (for example, LTE (Long Term Evolution), LTE-A (LTE-Advanced), and the like) may be a high-speed and high capacity communication system that is capable of transmitting and receiving various data (such as image data, wireless data, and the like) beyond providing a sound-based service. Accordingly, there is a desire for a technology that transmits high capacity data that is comparable to a wired communication network. Data may be efficiently transmitted through a plurality of component carriers as a scheme for transmitting high capacity data. In a TDD (Time Division Duplex) system, transmission (Tx) and Reception (Rx) may be executed using a predetermined frequency band. In this instance, Tx and Rx of data may be executed by being distinguished based on a time slot.
Conventionally, all of the serving cells are configured based on an identical TDD UL-DL configuration, and thus, adjustment between cells may not be needed. However, when different TDD configurations are configured for different carriers, or when a predetermined cell is configured as FDD and the other cell is configured as TDD, additional handling may be required since the TDD uplink/downlink subframe is limited in terms of time. That is, there is a desire for a method of controlling a downlink HARQ timing of a CA system.